The invention pertains to a nozzle element for windshield wiper system of a motor vehicle, with a ball-like body that transitions into a cylindrical projection with a central flow channel. Windshield wiper systems are standard equipment on motor vehicles today. For reasons of cost and also because it is readily available, water is used as the spray and washing fluid. In the cold season, however, the water can freeze, for which reason additives in the form, for instance, of alcohol and other volatile substances, can be added, at least in that season. There are also nozzles with heating, but here considerable expense is necessary.
In the case of water with a volatile additive, care must be taken that the latter does not evaporate, with the consequence that the nozzle freezes up. Therefore, so-called rubber-lip valves were developed, as described, for instance, in DE 39 35 318 A1 or DE 44 24 075 A1.
The disadvantage of these rubber-lip valves, which indeed do effectively prevent the evaporation of alcohol or the like, is that the spray jet exits from the valve in a relatively uncontrolled manner.
Accordingly there exists the problem of refining a nozzle element having the advantages of rubber-lip valve so that a controlled jet from the nozzle onto the windshield is possible.
To solve this problem, it is proposed according to the invention that the nozzle element includes a xe2x80x9cball-like bodyxe2x80x9d inserted into a nozzle body of known type, which can be deduced in principle, for instance, from the cited publications, for which reason a presentation in the context of the present invention and a detailed description can be dispensed with.
In the nozzle element according to the invention the washing fluid is supplied via the centered flow channel and then reaches the inner surface of the tubular resilient sleeve via at least one transverse channel. In case of non-use of the washing system or low fluid pressure, the resilient sleeve closes the outer opening of the transverse channel or of each transverse channel, so that no fluid can escape or evaporate. If, however, a sufficiently high pressure is input into the flow channel possibly, for instance, with the aid of a pump that can be operated by the driver, then the resilient sleeve bulges outward and the fluid can then flow out in the annular space between the sleeve and the cylindrical projection towards the open end of the nozzle element. In contrast to the flat, directly contacting lips of the known rubber-lip valve, which generate a flat jet of undefined cross-sectional shape, the fluid escapes in an orderly manner from the nozzle element in an annular jet. Thereby the jet direction can then be securely adjusted and the impact point on the windshield precisely fixed, even in case of a nozzle element seated adjustably in the nozzle body.
If it is stated that the tubular resilient sleeve reaches roughly up to the free end of the cylindrical projection, then there is the possibility of either actually extending the sleeve up to the free end or causing the sleeve to end slightly before that point or possibly allowing the sleeve to jut slightly past the free end surface. In the illustrated embodiments, however, the latter-mentioned alternative is not provided.
A refinement of the invention includes an annular bead which ensures, in conjunction with the circumferential annular groove of the nozzle element, the secure axial fixation of the resilient sleeve, even for the greatest possible fluid pressure. Additionally, the annular bead brings about a reinforcement of the inner area, particularly the inner end of the resilient sleeve, so that for the normal opening area of the transverse channel or channels situated further outward, the fluid cannot flow inward but only outward.
Preferably, the external annular groove is situated at the transition from the ball-shape basic body to the cylindrical projection.
In a preferred embodiment of the invention a centering of the spray jet is achieved, in particular, by the truncated conical free end of the cylindrical projection.
An additional improvement, namely a centering and guidance of the spray jet, is achieved by splitting the spray jet here into a number of smaller individual jets, which are brought together by the appropriate shaping and channel construction and then strike the windshield all together. This increases the cleaning effect in conjunction with the motion of the windshield wiper.
Another variant of the invention, illustrated in the drawing, likewise generates a directed jet of liquid, which is wider overall than that of the other embodiments and can find use anywhere where a larger jet diameter is desired. Depending on the construction of the recess, the latter feature can also be achieved with the aforementioned variants. The channels of the aforementioned third variant can expediently run at an incline, as expressed in the drawing.
In order to make adjustments easily for an adjustable nozzle element, it is provided that a blind hole be provided, preferably running coaxially to the flow channel and opening at the free end of the cylindrical projection, into which an adjustment instrument, such as a stiff piece of wire, a nail, a spike or the like, can be inserted.